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22 year-old male complains of severe cramping and increased fatigue…
22 year-old male complains of severe cramping and increased fatigue
Vegan Diet mostly fruit juices
pros
does get glucose
alternative sources of some nutrients
Cons
not getting enough protein
not enough calcuim
does not get enough nutrients to supply his muscles causing fatigue cramps and muscle loss
not having enough calcium magnesium or potassium
Organ Level of Skeletal Muscle
Epimysium
Layer of Dense Irregular CT surrounds whole skeletal muscle protects and supports
Perimysium
Layer of Dense of Irregular CT surround each fascicle protects and supports each bundle of muscle fibers
Endomysium
Areolar CT surround each muscle fiber electrically insulates the muscle fibers
Tendon
thick cord-like attaches muscle to bone
Aponeurosis
thin flattened sheet of dense irregular CT attach muscle to bone
Deep Fascia
sheet of Dense Irregular Ct external to epimysium separates each muscle binds together muscles contains blood vessels nerves lymph vessels and fills space b/t muscles
Superficial Fascia
composed of Areolar Ct and Adipose CT separates muscle from skin
Muscle Fiber Types
Slow Oxidative Fibers
contain slow ATpase produce slow and less powerful contractions can contract over long periods of time
Fast Oxidative Fibers
fast myosin ATPase fast and powerful contractions
Fast Glycolytic Fibers
fast myosin ATPase and provide both speed and power contract for only short bursts
Effects of Exercise
Endurance Exercise
sustained moderate activity increase heart rate changes how energy is supplied to skeletal muscle fibers are supplied
1.) increase of mitochondria enhances ATP production
2.) increase of enzymes for using fatty acids
3.) increase of lactate dehydrogenase enzyme
Resistance Exercise
involves forceful muscle contractions results in stronger skeletal muscle stimulates skeletal muscle fibers to increase contractile proteins
Hypertrophy
increase of muscle size
Hyperplasia
increase in number of muscle fibers
Atrophy
decreasing of muscle fiber size
Physiology of Skeletal Muscle
Neuromuscular Junction Excitation of a Skeletal Muscle Fiber
Ca ion enter synaptic knob
A nerve signal is propagated down motor axon triggers the entry of Ca ions into the synaptic knob Ca ion binds to proteins in synaptic vesicle membrane
Releases of ACh from synaptic knob
Calcium binding triggers synaptic vesicles to merge w/ the synaptic knob plasma membrane and ACh is exocytosed into synaptic cleft
binding of ACh to ACh receptor at motor end plate
ACh diffuses across the fluid-filled synaptic cleft at the motor end plate(MPE) to bind with ACh recteptors
Sarcolemma, T-Tubules and Sarcoplasmic Reticulum Excitation-Contraction Coupling
1.) Development of end-plate potential (EPP) at the motor end plate
binding of ACh to ACh recptors in MPE triggers the opening of these chemically gated ion channels. Na ions rapidly diffuses into and K ions slowly diffuses out of the muscle fiber
An EPP is produced when sufficient Na ions enters at MEP and the MP changes from -90mV to -65mV (the threshold)
2.) Initiation and propagation of an action potential along sarcolemma and t-tubules
The EPP intiates an AP to be propagated along the sarcolemma and t-tubules.
First, voltage-gated Na ions channels open, and Na ions moves in to cause depolarization.
Second, voltage-gated K ion channels open, and K ion moves out to cause repolarization
3.) Release of Ca ion from the sarcoplasmic reticulum
the AP is the propagated along the T-tubules to stimulate voltage-sensitive Ca ion channels, which trigger the opening of Ca ion release channels located in the terminal cisternae of the SR. Ca ion diffuses out of the cisternae of SR into cytosol.
3.) Sarcomere Crossbridge Cycling
1.) Ca ion binding
Ca ion binds to troponin in muscle thin filaments, causing a conformational change in troponin. Troponin changes shape and the entire troponin-tropomyosin complex is moved- tropomyosin no longer covers binding site
2.) Crossbridge Formation
Myosin heads binds to the exposed myosin binding site on actin forming a crossbridge b/t myosin and actin
Crossbridge
binding of myosin heads b/t thick and thin filaments
3.) Power Stroke
the myosin head swivels toward the center of the sarcomere pulling along the attached thin filament this motion is called a power stroke ADP and P are released during this process
4.) Release of myosin head
ATP binds to the ATP binding site on the myosin head which causes the release of the myosin head from the binding site on actin
5.) Reset of myosin head
ATp is split into ADP and P by myosin ATpase. This provides the energy to reset the myosin head
Skeletal Metabolism
Creatine Phosphate
chemical providing muscle cells with energy
Glycolysis
stage of cellular respiration in which glucose is partially catabolized to form pyruvic acid and to form ATP molecules
Aerobic Cellular Respiration
breakdown of glucose or other nutrients to produce ATP water and carbon dioxide requires oxygen
Lactate Formation
low oxygen levels due to high intense exercise conversion of lactate molecules
Lactate dehydrogenase
pyruvate molecules are converted to lactate molecules
Relaxation
1.) termination of rapid nerve signals
2.) Calcium channels close
3.) Troponin returns to original shape
Oxygen Debt
amount of additional oxygen that is consumed following exercise to restore pre-exercise conditions
Means of supplying ATP
Oxidative Fibers
providing ATP through Aerobic cellular respiration able to have muscle contract for long periods of time
Fatigue-resistant
contraction of muscles without tiring
Glycolytic Fibers
providing more ATP
Fatigable
tire easily after a short time of contraction
Organelle Level/Chemical
Sarcoplasm
cytoplasm of the skeletal muscle fibers
Sarcolemma
plasma membrane of skeletal muscle fiber
Transverse Tubules
t-tubules invaginations of the sarcolemma allows action potentials to approach and stimulate the sarcoplasmic reticulum
Myofibrils
bundles of myofilaments w/in skeletal muscle cells
Sarcoplasmic Reticulum(SR)
is an internal membrane complex similar to Smooth ER
Terminal Cisternae(tc)
blind sacs at the ends of SR
Triad
two tc and t-tubules
Voltage Sensitive Ca ion channels
responsive to electrical signals
Calcium Ion Release Channels
Release Ca ions from SR initiates muscle contractions
Myofilaments
a protein filament that makes up the myofibrils
Thick Filaments(TF)
made up of myosin extend the length of the muscle fibers
Myosin
fibrous protein forms the contractile filaments of muscle cells
Thin Filaments
made up of actin interaction of myosin regulation of force and transmission of force
Actin
twisted around each other to form fibrous strand
Myosin Binding Sites
myosin attaches during contraction
Troponin
globular attached to tropomyosin binding site for Ca ions
H Zone
thick filament present central part while resting
Tropomyosin
short thin twisted filament cover myosin binding sites
Sacromere
an arrangement of myofibrils in repeating cylindrical units
Z Disk
position perpendicular to myofilaments and serves as anchors for thin filaments
I bands
light bands made up of thin filaments pulled parallel to thick filaments
A bands
central region thick filaments does not change during contraction
M Line
thin transverse meshwork in the middle of the H Zone
Connectin
"cablelike" protein extends from Z disks to M Line through thick filaments stabilizes position of TF and maintains alignment
Dystropnin
anchors myofibrils adjacent to sarcolemma link internal myofilament to external proteins
Myoglobin
Oxygen-carrying and -storing molecule in muscle
Synaptic Knob
expanded tip of an axon
Synaptic Vesicles
filled with acetylcholine
Acetylcholine(Ach)
neurotransmitter causes muscles to contract
Motor End Plate
folds and indentions increase surface area has ACh receptors
ACh receptors
voltage gated channels allowing Na ions to be let in while K ions are released
Synaptic Cleft
separates the synaptic knob and motor end plate
Acetylcholinesterase
breaks down ACh
Resting Membrane Potential
electrical charge difference when the cell is at rest
Neuromuscular Junction
mid-region of skeletal muscle fiber where it is innervated by a motor neuron has the synaptic cleft synaptic knob and motor end plate
Muscle Fatigue
Insufficient free Ca ions ay neuromuscular junction to enter synaptic knob or decrease of synaptic vesicles to release neurotransmitters limit somatic motor neurons to stimulate skeletal muscle
change in ion concentration interferes w/ ability of muscle fibers to conduct and AP along sarcolemma interferes w/ stimulating release if Ca ions from SR
increase of phosphate ion concentration Elevated P interferes with crosssbridge cycling lower amounts of Ca ions resulting in weaker contractions
Intense weight trainging
pros
gain muscle mass
better coordination
strengthen immune system
Cons
poor heart condition
poor breathing
this will cause fatigue and muscle cramps by overworking the muscles
Skipping Meals
Pros
there are no pros to skipping meals
Cons
not getting enough nutrients
Always hungry
this will lead to fatigue muscle loss and cramping because of lack of nutrients
Drinking a gallon of water
Pros
stay hydrated
keeps the body regulated
Cons
losing sodium
causing weight loss
Sleep distruption
cause fatigue
Avoids Sports Drinks
Pros
getting less sugar
Cons
not getting the sodium
cause muscle cramps and fatigue
not getting enough sugar
causes fatigue
Skipping meals after workout
lose even more weight
skeletal system will be affected
Organ Systems affected
Avoiding Sports Drinks
will not be able to completely contract muscle
muscle and skeletal will be affected
Intense Workout
cause severe muscle cramps and fatigue
muscle skeletal
Vegan Diet
the nutrients will not be replenished
Organ skeletal muscle
Gallon of water
over hydrating the body
losing sodium and potassium
muscle